Effects of the polarization fields on the responsivity of the AlN/GaN photodetectors

AlN/GaN heterostructures and GaN monolayer photoconductive detectors were fabricated. The effect of the AlN/GaN interface polarization fields on the responsivity of the photodetector was investigated. The existence of two-dimensional electron gas (2DEG) in AlN/GaN heterostructures was proved by variable temperature Hall measurement. The spectral responses of the two samples were measured. The maximum responsivities of the AlN/GaN heterostructure photodetector at 360 nm were 2430 A/W (3V), which is much higher than GaN monolayer photodetector (206 A/W at 363 nm under 3 V). The main reason is that a strong polarization fields was formed in the AlN/GaN heterostructure interface.